great crested newt survey

Great Crested Newt Survey – Habitat Suitability Index

Great Crested Newt Survey

Determining the probability of great crested newts being present in ponds can be achieved by examining habitat features of ponds such as the presence of fish, waterfowl and water quality.

Habitat Suitability Index Assessment for Great Crested Newt

Acer Ecology can undertake Habitat Suitability Index Assessments (HSI after Oldham et al., 2000) for great crested newts. These surveys can be undertaken throughout the year and enable us to rapidly assess the value and potential of a pond to support great crested newts.

How does Acer Ecology Undertake a Habitat Suitability Index Survey?

During the HSI assessment, a score is produced between 0 and 1, where 0 represents habitats of low value (low potential for great crested newt) and 1 represents habitats of high value (high potential for great crested newt). Good or excellent ponds are very likely to be occupied by newts and further survey work may be required. Poor ponds are rarely occupied and further survey work is not usually required.

These scores are based on several factors which affect the suitability of a pond. These factors include:

  • Geographic locationgreat crested newt pond
  • Pond area
  • Permanence of pond
  • Water quality
  • Shade
  • Presence of waterfowl
  • Presence of fish
  • Number of ponds within 1km
  • Terrestrial habitat quality
  • Macrophyte cover (e.g. emergent and floating plants)
For Example:
Pond 1– An Excellent Pond for Great Crested Newts

Dries rarely, good water quality, no fish or waterfowl, partial shade and moderate macrophyte cover and surrounded by rough grassland.poor great crested newt pond

Scores higher than:

Pond 2 – A Poor Pond for Great Crested Newt

Dries annually, poor water quality, fish present, heavy shade, low  macrophyte cover and surrounded by mown grassland

Pond 1 is more suitable for supporting a great crested newt  population

Habitat Suitability Assessments Can Help Avoid Delays

HSI assessments are NOT a substitute for newt surveys, but they provide guidance on whether further newt surveys should be undertaken – this can help avoid delays to your project, and potentially reduce the cost.

Habitat Suitability Assessments Are Useful in:

  • Evaluating the general suitability of a pond
  • Comparing ponds on a site
  • Evaluating the suitability of receptor ponds in a mitigation scheme
  • Developing habitat management plans

Contact Acer Ecology’s great crested newt specialists on 029 2065 0331 or For more information, click here for examples of our work and for more information about the Ecology Services we can offer and how we can help you carry out great crested newt surveys.